In the packaging industry, distributors seek to offer an ever more diversified range of packaged products whilst increasing production rates. Therefore, it is important to be able to quickly adjust a packaging device so that it can package products in a large number of ways. Here, more specifically speaking, the interest is placed on the number of articles packed together, in fact the distributors often offer a large choice of packages for the same product: bottles presented in packs of two, three or six, for example.
A system is already known for transporting the articles one by one to a grouping device for forming and spacing out the batches of articles then transporting the batches to a unit thereby allowing their packaging.
To do so, the grouping device is so arranged as to group together a given number of articles forming a batch then to increase the transportation speed for the batch in order to space it out from the following batches.
In document EP-1 116 675, the grouping system is presented in the form of a cogged wheel in which each cog can be speeded up to space one batch away from the following one. However in such a device, the spacing between the cogs is substantially constant, which does not allow the number of articles per batch to be adjusted easily. To change this number, in fact it is necessary to dismount the cogged wheel to change the number and/or the distribution of the cogs on the wheel.
In document EP-0 860 385, the grouping device includes a rotating system including several sectors, each one moved in rotation by a rotating shaft linked to a motorised unit the speed of which is controlled. Thus a first sector drives along several articles, then this sector is speeded up by its rotating shaft in order to separate it from the following sector which is still performing the step of forming the following batch.
Such a device allows the space between each batch to be chosen by selecting a suitable speed profile. However, each sector is provided for forming a batch including a given and constant number of articles. Such a device is therefore difficult to adapt and does not allow the number of articles per batch to be modified without changing the parts that form the device.
Furthermore, the devices described above allow the articles to be pushed upstream, but not to retain them downstream, which may mean that some articles fall off the device.
Devices for grouping batches of articles together are also known from documents U.S. Pat. No. 3,482,674, EP-1 153 859, U.S. Pat. No. 5,699,651 and U.S. Pat. No. 6,443,689. Anyway, these devices do not allow batches to be formed for which the number of articles is adjustable whilst the device is working using rotating transfer systems.